This invention relates to a method and an apparatus for forming and conveying groups of face-to-face contacting flat articles, particularly confectionery items such as biscuits, crackers or cookies. The manufacturing apparatus, such as a baking oven, discharges the items in a flat-lying orientation onto a first conveying mechanism which delivers them to a stacking device in which an article stack is formed. The article stack is then advanced on a second conveyor to a packing machine. The stacking apparatus comprises an abutment against which the articles supplied by the first conveyor abut, a sensor responding to the passage of an article on the first conveyor and a mechanism for a stepwise advance of a stack-forming unit.
A method and an apparatus as outlined above is described, for example, in German Offenlegungsschrift (non-examined published application) 2,713,205. The apparatus is arranged immediately upstream of a packing machine and forms, from a column of biscuits delivered by a baking oven, a biscuit stack by means of a stack-forming unit. The latter comprises two spoked (star-shaped) rollers which rotate in opposite directions with respect to one another, about respective axes oriented parallel to the direction of article advance. The articles are, by means of a first conveyor belt, pushed into longitudinally extending recesses of the rollers and abut a stop provided with a sensor. When the pressure on the sensor has attained a predetermined value, the rollers are stepwise rotated by one division so that the article column situated in the rollers is lifted or lowered and the subsequent articles are pushed into the next opening of the star-shaped rollers When the article stack has reached a predetermined height, a ram pushes the stack transversely to the direction of conveyance of the first conveyor belt onto a second conveyor belt which advances the stack to the packing machine.
The above-outlined known apparatus has a very small storing capacity because the articles are advanced to the stack-forming unit in columns in a flat-lying orientation and these columns may contain only few items for a determined length. A large storage capacity, however, is desirable, particularly for an optimal utilization of the capacity of the packing machine to permit absorption of short-period stoppages and, in case of longer standstills, a switchover to a standby packing machine should be possible without generating waste.
Apparatus having a significantly increased storage capacity are known, for example, from British Patent No. 2,044,230 which teaches that the biscuits, after emerging from the baking oven, are arranged to form a column in an edgewise upstanding, face-to-face contacting orientation. The column may then be advanced via storage tracks, deflector switches and dosing devices to the packing machines, as described, for example, in U.S. Pat. No. 4,209,960 or British Patent No. 1,413,970. It is a disadvantage of these arrangements that the biscuits are exposed to significant stresses on the conveyor tracks.
U.S. Pat. No. 4,662,152 discloses an apparatus for forming an article stack in a packaging container. As in the earlier-noted German Offenlegungsschrift No. 2,713,705, the articles are supplied to the stacking apparatus on a conveyor belt, forming a column thereon, in a flat-lying, longitudinally spaced orientation. The terminal length portion of the conveyor belt is pivotal and is, in synchronism with the incoming articles, stepwise lifted so that the articles may be inserted into the laterally open packaging containers from the bottom upward. In order to ensure such synchronism, upstream of the conveyor belt abutment fingers are arranged which arrest the articles and permit advance thereof to the conveyor belt in a predetermined cadence. In this arrangement too, the storage capacity is significantly limited